Play it safe in the backcountry by learning how to determine whether snow conditions are prone to avalanche
The exhilaration of hitting backcountry slopes comes with the looming risk of triggering an avalanche. Learning how to read the clues hidden in snowpack can reduce the risk of being caught in a slide. Assessing avalanche danger is a science that recognizes variables in snow quality to indicate signs of potential avalanche danger. Identifying these variables is an acquired skill. If you intend to ski or snowboard in the backcountry, it is highly advisable to take an avalanche course and learn from experts.
As a rule, the cohesiveness of the snow can tell a lot about its avalanche potential. Is it loose? Does it clump together? Is it wet or dry? Consider the texture: is it grainy or fluffy, or densely packed? Snow that is not well-bonded is unstable and poses the risk of avalanching. Another consideration is how the snowpack will behave when it is disrupted at different slope angles.
LOOSE SNOW AVALANCHE
Wet or dry snow that does not bond well can result in “loose snow’” avalanches. These loose snow avalanches result from snowpack accumulated during snowstorms in cold months, although they can also develop in melting snowpack or from precipitation in warmer months. They occur at or near the surface and gain momentum as they cascade, typically forming a triangular pattern as seen from above. Something as simple as a tuft of tumbling snow can set one off as can the softening that occurs in a melting snowpack.
If you observe snowballs tumbling down a slope on a sunny day, you may want to reconsider your day. This is a sign of “surface warming’” and it has the potential to result in a slide.
SLAB AVALANCHE
Snowpack with layers that could be described as “grainy” or “fluffy” or even “dry” and “icy” may indicate weakness, and could result in a “slab avalanche”. Such is the result of one layer not bonding with the layer beneath it, thus fracturing and sliding away in a sweeping, often huge, slab. These avalanches occur with more depth, scale and density, posing an even greater threat to backcountry travelers than that of loose snow. Often, these are the slides triggered by adventurers who have ventured onto the slopes.
Be on the lookout for signs of unstable snow such as surface fractures forming around feet or equipment, or patterns made by strong winds, which could indicate an unbonded layer of wind-carried snow. Listen for sounds, often described as “whumping”, while walking on the snow. Sounds like this indicate the snow is in the process of settling and has points of weakness.
SLOPE
Avalanches tend to occur on slope angles between 30 to 45 degrees (a clinometer is an easy way to measure degree). Slope aspect is also a consideration: does the slope face north or south, and how does sun exposure affect these slope aspects at different times of the year? During the winter months, a south-facing slope is much safer than a north-facing slope. Why? This is due to the lack of sun exposure on the north side. Without sun, the snow cannot condense. Loose, unstable layers of dry, icy snow is known as “depth hoar.” In the warmer months, however, the south-facing slopes have an increased risk of wet-snow slides from melting snowpack.
Of course, reading snowpack requires skill and experience. Performing snow tests should first be practiced with an expert, or learned by taking a course.
LIS MCLAUGHLIN is a full-time manufacturer in the cannabis industry and freelance writer based in Durango, Colorado. In her free time, she is an outdoor recreationalist, fitness enthusiast and avid pursuer of knowledge.
